杨梅酮对高脂诱导的肥胖小鼠脂肪肝的预防作用

研究杨梅酮(Myricetin,MTN)对高脂诱导的肥胖小鼠脂肪肝的预防作用。32只C57BL/6J雄性小鼠随机分为4组:对照组(CT,饲喂正常日粮),对照+杨梅酮组(CT+MTN,饲喂含质量分数0.2%杨梅酮的正常日粮),高脂组(HF,饲喂高脂日粮),高脂+杨梅酮组(HF+MTN,饲喂含质量分数0.2%杨梅酮的高脂日粮)。10周后测定小鼠代谢差异(能量消耗、呼吸交换率、自主活动),血脂水平,肝脏氧化还原状态及脂质沉积情况,同时采用q PCR检测小鼠肝脏脂质代谢相关基因的表达。结果表明与对照组相比,长期高脂日粮导致小鼠体质量显著增加,内脏脂肪沉积,能量消耗显著降低(P0.05)。肝脏发生氧化应激,表现为MDA显著上升,GSH-Px、SOD、CAT、GSH显著下降(P0.05)。肝脏脂肪变性,肝脏甘油三酯(TG)、总胆固醇(TC)、游离脂肪酸(FFA)水平均显著高于对照组,脂质合成相关基因(Acc1、Fasn、Srebf1)显著上调,脂肪酸氧化相关基因(Cpt1α、Pparα)显著下调。高脂日粮基础上添加杨梅酮能够恢复肝脏TG、TC、FFA水平及肝脏脂质代谢相关基因(Acc1、Fasn、Srebf1、Cpt1α)的表达,同时维持肝脏的氧化还原状态。因此,推测杨梅酮可能通过维持肝脏氧化还原状态,促进能量消耗,调节肝脏脂质代谢,预防脂肪肝的发生。     

Finite Element Analysis of Ceramic Coatings under Spherical Indentation with Metallic Interlayer: Part Ⅰ Uncracked Coatings

Spherical indentation of ceramic coatings with metallic interlayer was performed by means of axisymmetric finite element analysis (FEA). Two typical ceramic coatings with relatively high and low elastic modulus deposited on aluminum alloy and carbon steel were considered. Various combinations of indenter radius-coating thickness ratios and interlayer thickness-coating thickness ratios were used in the modeling. The effects of the interlayer, the coating and the substrate on the indentation behavior, such as the radial stress distribution along the coating surface as well as the coating interface, and the plastic deformation zone evolution in the substrate were investigated in connection with the above mentioned ratios. The coating cracking dominant modes were also discussed within the context of the peak tensile stresses on the coating surface and on the coating interface.     

强脉冲离子束在金属中引起的应力波效应

金属在强脉冲离子束辐照及其后的快速冷却过程中所经历的应力过程是强脉冲离子束金属材料改性的最重要的机制之一。对应于这种过程，金属材料的微观结构和微硬度发生了改变。本文以45＃钢和纯铝为样品，将实验中测量到的不同强度的强脉冲辐照后样品微硬度和微观结构的变化与热力学计算所描述的热力学过程相对照，解释了出现微硬度双峰是由于应力波的形成和传播使然，并预言了由于应力波的在样品背面的反射，在较强能通量的强脉冲离子束辐照下样品背表面一定深度处也会出现微硬度增加的现象，该现象已被实验所证实。     

分形几何和动力系统中的一些问题

本文是Zhou与Feng,Nonlinearity,2004的续篇,对自相似集的结构和动力系统提出一些较为深入的问题。     

Structural and functional properties of full-length and truncated human proapolipoprotein AI expressed in escherichia coli

Utilizing the Escherichia coli/pGex vector expression system incorporating a thrombin cleavage site, full-length (residues -6-243) and truncated forms of proapolipoprotein AI (proapoAI), terminating at amino acid residues 222, 210, 150, and 135, were purified to levels of at least 5 mg/L, after thrombin cleavage. Assessed by circular dichroism, the helical contents of L-alpha-dimyristoylphosphatidylcholine-associated forms of human plasma-derived apolipoprotein AI (apoAI) and recombinant proapoAI were comparable, being 69% and 65%, respectively. Circular dichroism measurements of the lipid-associated complexes of the truncated forms showed that between the sequence of residues 150-222 no additional helicity was gained until the carboxyl-terminal sequence was present in the molecule, indicating that the carboxyl terminus of the protein is required for the formation of helix within this central region. While tryptophan residues were more than 86% accessible, as assessed by iodide quenching, in the two truncated forms, proapoAI-6-135 and proapoAI-6-150, for both free and complexed protein, this figure fell to about 50% for full-length recombinant proapoAI, further indicating the influence of the carboxyl terminus on the structure of the whole protein. While cross-linking human plasma apoAI in solution with dithiobis-(succinimidyl propionate) revealed high molecular weight oligomers by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, recombinant proapoAI did not strongly form complexes larger than trimers. None of the truncated proapoAI molecules formed oligomers larger than trimers. The shortest form, proapoAI-6-135, only dimerized. Initial results from lecithin:cholesterol acyltransferase activation (apoAI peptide concentration 0.2 microM) indicated that truncation of the 21 carboxy-terminal amino acids resulted in a drop of approximately 53% in activation and 33 residues a drop of 67% relative to the full-length protein. Overall these results indicate the important influence of the carboxyl terminus on the structure of apoAI.     

The use of below-knee percutaneous transluminal angioplasty in arterial occlusive disease causing chronic critical limb ischemia

PURPOSE: To determine the efficacy, safety and long-term results of crural artery percutaneous transluminal angioplasty (PTA) in limbs with chronic critical limb ischemia (CLI). METHODS: Patients undergoing crural artery PTA due to CLI were followed at regular clinic visits with ankle brachial pressure index (ABPI) measurements. PTA of the crural arteries was attempted either alone (n = 39) or in combination with PTA of the superficial and/or popliteal artery (n = 55) in 86 limbs (82 patients and 94 procedures) presenting with CLI. The ages of patients ranged from 37 to 94 years (mean 72 years). The indications for PTA were rest pain in 10 and ulcer/gangrene in 84 limbs. RESULTS: A technically successful PTA with at least one crural level was achieved in 88% of cases (n = 83). Cumulative primary clinical success rates at 6, 12, 24, and 36 months were 55%, 51%, 36%, and 36%, respectively. Cumulative secondary clinical success and limb salvage rates at 36 months were 44% and 72%, respectively. CONCLUSION: PTA of the crural arteries might be considered the primary choice of treatment in patients with CLI and distal lesions with localized stenosis or segmental short occlusions.     

浊点萃取-原子吸收法测定水中微量的镉

基于5-Br-PADAP与镉形成稳定的螯合物能被TritonX-114浊点萃取的事实,建立了浊点萃取-原子吸收法测定水中微量的镉的新方法。镉的浓度在0.25～4.00μg/mL内呈线性,检测限为6.7μg/L;相对标准偏差（n=11）为2.7%,加标回收率为98.5%～102.3%。     

废旧电路板非金属材料的回收利用方法研究进展

概述了国内外废旧电路板回收利用的研究进展,分析了废旧电路板的成分和特性,介绍了废旧电路板回收利用的方法与工艺,最后指出在废旧电路板回收利用行业中存在的问题。     

聚丙烯酰胺降解菌筛选与分子生物学鉴定

从大庆油田聚驱后油藏采出水中筛选出一株降解聚丙烯酰胺的细菌菌株——QSJU001.该菌株能在以聚丙烯酰胺为惟一碳源的无机盐培养基中生长.对该菌进行16SrDNA序列的分子生物学鉴定,测得的16SrDNA序列与GenBank中最相近的前10个菌株的相似性均为99%.利用该菌属与最相近的前10个菌株构建该菌种的系统发育树,结果显示该菌株与Acinetobacter baumannii strain KK14菌株的碱基差别最小.该菌的形态特征观察、生理生化特征检测、16SrDNA分子生物学鉴定结果表明,菌株QSJU001与Acinetobacter baumannii strain KK14亲缘关系最近,属于不动杆菌属.降解率实验结果表明,菌株QSJU001对聚丙烯酰胺降解率基本稳定在33%左右,对聚丙烯酰胺的降解效果较好.     

聚乙烯材料的拉伸疲劳动力学模型

高分子材料的疲劳破坏过程无论是机理还是现象都与金属材料有较大的不同,不能将金属的疲劳曲线[应力-寿命(S-N)曲线]的拟合模型直接用于高分子材料。在微观缺陷集中的动力学模型基础上进行修正,提出了存在平均应力下的高分子拉伸疲劳动力学模型,并应用于一种聚乙烯材料的拉伸疲劳试验中。结果表明,该模型能够准确地描述聚乙烯材料的拉伸疲劳行为,并且具有良好的稳定性。